What is a family preference category? Qualified relatives of a U.S. citizen or permanent resident who are not known as an immediate relative may have to wait for a visa to become available before they can apply for permanent residency. These categories are known as Preference Categories and include:
Sedimentary rocks are formed by sediment that is deposited over time, usually as layers at the bottom of lakes and oceans. This sediment can include minerals, small pieces of plants and other organic matter. The sediment is compressed over a long period of time before consolidating into solid layers of rock. Sedimentary rocks forms layers called strata which can often be seen in exposed cliffs.
Clastic or detrital sedimentary rocks are made of sediments that are the result of weathering and transport. Chemical rocks are created from chemical precipitation. Biochemical or organic rocks are made up biological remains. sedimentary structure is a structural feature in a sedimentary rock formed as a result of weathering or transportation. Types of sedimentary structures include: stratification, cross bedding, graded bedding, ripple marks, oscillation marks, mud cracks, raindrops, and trace fossils.